Go to Vault 22, take the elevator down to Pest Control (level 5?), and your companion should be there... why I don't know, but this is a confirmed fix.
Why won't the board mods make a maintained sticky post with these player discovered fixes so
that people with the issues can find a answer without spending hours weeding through all these posts?
Rhetorical question I don't expect you to have an answer.
Perhaps one of the mods might consider the kindness of the purchasers of the game to do something like this though.
It might help me consider Bethesda in a more positive light in the future for possible game purchases.
At this stage I"ve stopped playing the game and am hoping they manage to fix it to playable (tolerable) for me MONTHS after I bought it.
So, feel free to improve my feelings, Bethesda.